Pouch-type secondary battery and battery module comprising the same

ABSTRACT

A pouch-type secondary battery includes an electrode assembly; and a pouch member comprising an accommodating portion configured to accommodate the electrode assembly therein, a sealing portion formed at an edge of the accommodating portion, and an indent portion formed of a cutting edge cut at a plurality of angles and a rounded edge cut to connect the cutting edges adjacent to each other in a portion of the sealing portion corresponding to a vertex of the accommodating portion.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The application claims benefit of priority to Korean Patent ApplicationNo. 10-2019-0063766 filed on May 30, 2019 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND 1. Field

The present disclosure relates to a pouch-type secondary battery and abattery module including the same.

2. Description of Related Art

With increased demand for mobile devices along with the development ofrelated technologies, demand for a secondary battery as an energy sourcehas rapidly increased. A secondary battery may be repeatedly charged anddischarged as mutual conversion between chemical energy and electricalenergy is reversible in a secondary battery. A pouch member of asecondary battery refers to a laminated film case for protecting apositive electrode, a negative electrode, a separation film, and anelectrolyte solution, i.e., the main components of a secondary battery.

Such a pouch member has been used as a case of a lithium ion polymerbattery or a dual-layer electrical capacitor. To use a secondary batteryas a battery for a vehicle or a battery for an energy storage system, ithas been necessary to secure long-term durability, durability sustainedfor 10 years or longer.

Meanwhile, as higher specifications are required for a high-capacity andhigh-power secondary battery, it has been necessary to develop asecondary battery able to implement high-energy density andhigh-performance cooling in accordance with the above-describedrequirements.

To satisfy such specifications, a measure of installing a secondarybattery having high density has been considered; however, there may aproblem arising in that the battery capacity may be relatively reducedin terms of the area occupied by the sealing portion in the case of apouch-type secondary battery.

Accordingly, to address the above-described issues and limitations,research into a pouch-type secondary battery and a battery moduleincluding the same may be necessary.

SUMMARY

An aspect of the present disclosure is to provide a pouch-type secondarybattery, in which the problem of battery capacity relatively reduced byan area occupied by a sealing portion is resolved and a battery moduleincluding the same.

According to an exemplary embodiment of the present disclosure, apouch-type secondary battery may include an electrode assembly; and apouch member comprising an accommodating portion configured toaccommodate the electrode assembly therein, a sealing portion formed atan edge of the accommodating portion, and an indent portion formed of acutting edge cut at a plurality of angles and a rounded edge cut toconnect the cutting edges adjacent to each other in a portion of thesealing portion corresponding to a vertex of the accommodating portion.

The indent portion of the pouch-type secondary battery according to anexemplary embodiment may be formed adjacently to both sides of a leadtab portion of the electrode assembly externally exposed while beingconnected to the electrode assembly.

Specifically, the indent portion may include a first cutting edge formedto be inclined in a direction away from the lead tab portion; and asecond cutting edge connected to the first cutting edge via the roundededge and formed at a gentle angle of inclination as compared to an angleof inclination at which the first cutting edge is formed.

The first cutting edge of the indent portion according to an exemplaryembodiment may have an angle of inclination of 10° to 50° with respectto one edge of the accommodating portion adjacent to the lead tabportion.

The second cutting edge of the indent portion may have an angle ofinclination of 5° to 15° with respect to one edge of the accommodatingportion adjacent to the lead tab portion.

Further, the pouch-type secondary battery according to an exemplaryembodiment may have the first cutting edge formed closer to the lead tabportion and shorter as compared to the second cutting edge.

In the pouch member of the pouch-type secondary battery, when the leadtab portion is arranged adjacent to one edge of the accommodatingportion and is offset to one side, a cutting edge of the indent portionformed in an area enlarged by the offset arrangement of the lead tabportion may be formed at a gentle angle of inclination as compared to acutting edge of the indent portion formed in an area reduced by theoffset arrangement of the lead tab portion.

In addition, the rounded edge of the pouch-type secondary battery may beformed to have a radius of curvature of 2 mm to 8 mm.

According to another exemplary embodiment of the present disclosure, abattery module may include the pouch-type secondary battery and ahousing member accommodating a plurality of the pouch-type secondarybatteries therein.

The indent portion of the battery module according to another exemplaryembodiment is formed in a position corresponding to a protrusion portionprovided in the housing member.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages of the presentdisclosure will be more clearly understood from the following detaileddescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a planar view illustrating a portion adjacent to an indentportion in a pouch-type secondary battery of the present disclosure;

FIG. 2 is a planar view illustrating the pouch-type secondary battery ofthe present disclosure;

FIG. 3 is a planar view illustrating an exemplary embodiment in which alead tab portion in the pouch-type secondary battery is offset; and

FIG. 4 is a planar view illustrating the pouch-type secondary batteryand a battery module including the same.

DETAILED DESCRIPTION

Hereinafter, example embodiments of the present disclosure will bedescribed with reference to the accompanying drawings. The presentdisclosure is not limited to example embodiments, and it is to beunderstood that modifications can be made without departing from thespirit and scope of the present disclosure. Shapes and sizes of theelements in the drawings may be exaggerated for clarity of description.

In addition, an expression used in the singular encompasses theexpression of the plural, unless it has a clearly different meaning incontext. Identical or corresponding elements will be given the samereference numerals.

The present disclosure relates to a pouch-type secondary battery 100 anda battery module including the same. A problem of battery capacityrelatively reduced by an area occupied by a sealing portion 122 in thepouch-type secondary battery 100 may be remedied.

In another aspect, the pouch-type secondary battery 100 and the batterymodule including the same in some exemplary embodiments may preventfolding of the sealing portion 122 by defining a shape and a size ofcutting edges 123 a and 123 b forming an indent portion 123.

Meanwhile, in some exemplary embodiments, a pouch-type secondary battery100 and a battery module including the same may prevent burring orcracking from occurring by defining a shape and a size of a rounded edge123 c when an indent portion 123 is formed.

Specifically, with reference to the drawings, FIG. 1 is a planar viewillustrating a portion adjacent to an indent portion 123 in thepouch-type secondary battery of the present disclosure. Based on FIG. 1, the pouch-type secondary battery 100 may include an electrode assembly110; and a pouch member 120 comprising an accommodating portion 121configured to accommodate the electrode assembly 110 therein, a sealingportion 122 formed at an edge of the accommodating portion 121, and anindent portion 123 formed of cutting edges 123 a and 123 b cut at aplurality of angles and a rounded edge 123 c cut to connect the cuttingedges 123 a and 123 b adjacent to each other in a portion of the sealingportion 122 corresponding to a vertex of the accommodating portion 121.

As described above, the pouch-type secondary battery 100 includes theindent portion 123, and the indent portion 123 is formed of the firstcutting edges 123 a and 123 b, and the rounded edge 123 c formed betweenthe first cutting edges 123 a and 123 b.

Accordingly, a problem in which an entire size of the pouch-typesecondary battery 100 is reduced due to an insufficient installationspace by a protrusion portion 210 formed to fasten inside the housingmember 200, which may arise when the pouch-type secondary battery 100 isbuilt in a housing member 200, or the like, of a battery module, may beremedied.

That is, in order to remedy the problem in which a maximum size of thepouch member 120 is reduced because the sealing portion 122 is caught bythe protrusion portion 210, the indent portion 123 is formed in aportion corresponding to a position of the protrusion portion 210 toincrease a size of the accommodating portion 121 of the pouch member120, thereby increasing capacity of the electrode assembly 110.

In addition, the pouch member 120 of the present disclosure is formedwith the rounded edge 123 c between the cutting edges 123 a and 123 b inorder to prevent a problem of occurrence of burring or cracking betweenthe cutting edges 123 a and 123 b when forming the cutting edges 123 aand 123 b for formation of the indent portion 123.

The electrode assembly 110 may be configured as a secondary battery inwhich mutual conversion between chemical energy and electrical energymay be reversible such that the electrode assembly 110 may be repeatedlycharged and discharged. The electrode assembly 110 may be implemented bya generally used secondary battery. For example, in the electrodeassembly 110, a negative electrode and a positive electrode may bealternately stacked with a separation film interposed therebetween, andsurfaces of the negative electrode and the positive electrode, coatedwith an electrode active material, may oppose each other.

The electrode assembly 110 may be substantially accommodated in thepouch member 120 together with an electrolyte solution. The electrolytesolution may include an organic solvent such as ethylene carbonate (EC),propylene carbonate (PC), diethyl carbonate (DEC), ethyl methylcarbonate (EMC), dimethyl carbonate (DMC), or the like, together with alithium salt such as LiPF₆, LiBF₄, or the like. Further, the electrolytesolution may be liquid, solid, or gel-type.

The pouch member 120 may accommodate and protect the electrode assembly110. To this end, the pouch member 120 may have a vessel form to providean internal space in which the electrode assembly 110 and an electrolytesolution are accommodated. A portion of a lead tab portion 111 of theelectrode assembly 110 may be externally exposed from the pouch member120.

Such configured pouch-type secondary battery 100, as a nickel metalhydrogen (Ni-MH) battery, a lithium ion (Li-ion) battery, or the like,which may be charged and discharged, generates current. Further, aplurality of the pouch-type secondary batteries 100 may be stacked inthe housing member 200.

In the pouch member 120, the sealing portion 121 may be disposed to sealan edge of the pouch member 120 in which the electrode assembly 110 isdisposed, thereby protecting the electrode assembly 110.

The sealing portion 121 may be configured to protrude horizontally fromall side surface of the pouch member 120, but may be configured to forman internal space followed by folding to seal three side surfaces, thatis, in a three side-sealed form.

As described above, the pouch member 120 may include the accommodatingportion 121, in which an internal space for accommodating the electrodeassembly 110 is formed, and the sealing portion 122 formed around theaccommodating portion 121 to seal the same.

In addition, the pouch member 120 includes the indent portion 123 in anarea of the sealing portion 122 corresponding to a vertex of theaccommodating portion 121. The indent portion can serve to prevent spaceloss by the protrusion portion 210 when mounted on the housing member120, thereby enlarging the accommodating portion 121 for increasedcapacity of the electrode assembly 110.

The indent portion 123 may be formed of a plurality of cutting edges 123a and 123 b cut at a plurality of angles and a rounded edge 123 cbetween the cutting edges 123 a and 123 b.

Such cutting edges 123 a and 123 b and the rounded edge 123 c may beformed by laser processing or by a one-press process using a die cutter.However, a method for manufacturing the indent portion 123 of thepresent disclosure is not limited thereto and may be any method as longas the indent portion 123 is formed as described above.

The indent portion1 123 of the pouch-type secondary battery 100according to an exemplary embodiment may be formed adjacently to bothsides of a lead tab portion 111 of the electrode assembly 110 externallyexposed while being connected to the electrode assembly 110.

In other words, the indent portion 123 is formed in a portioncorresponding to the protrusion portion 210 for coupling to a housing,among the protrusion portion 210 of the housing member 200. Suchprotrusion portion 210 is mainly disposed close to both sides of thelead tab portion 111 when the pouch-type secondary battery 100 is builtin the housing member 200, and thus, the indent portion 123 is formedclose to both sides of the lead tab portion 111.

Specifically, the indent portion 123 of the pouch-type secondary battery100 according to an exemplary embodiment may include a first cuttingedge 123 a formed to be inclined in a direction away from the lead tabportion 111 and a second cutting edge 123 b connected to the firstcutting edge 123 a via the rounded edge 123 c and formed at a gentleangle of inclination A2, as compared to an angle of inclination A1 atwhich the first cutting edge 123 a is formed.

That is, the first cutting edge 123 a adjacent to the lead tab portion111 may be formed at a greater angle of inclination A1 than an angle ofinclination at which the second cutting edge 123 b disposed further awayfrom the lead tab portion 111 than the first cutting edge 123 a.

This is to secure an area of the indent portion 123 by cutting andremoving a larger area from the sealing portion 122 when forming theindent portion 123 by cutting edges 123 a and 123 b.

Accordingly, a problem of a space limited by the indent portion 210 maybe more effectively remedied.

In addition, the first cutting edge 123 a of the pouch-type secondarybattery 100 according to an exemplary embodiment may have an angle ofinclination A1 of 10° to 50° with respect to one edge of theaccommodating portion 121 adjacent to the lead tab portion 111.

In other words, a range of the angle of inclination A1 of the firstcutting edge 123 a formed closer to the lead tab portion 111 than thesecond cutting edge 123 b is defined.

The angle of inclination A1 of the first cutting edge 123 a is definedas 50° or less so that a portion around the sealing portion 122, inwhich the first cutting edge 123 a is formed, is prevented from beingfolded by an external force.

The angle of inclination A1 of the first cutting edge 123 a is definedas 10° or above to extend an area of the indent portion 123 formed bythe first cutting edge 123 a to be a significant area. That is, theangle is defined to form the indent portion 123 in an area in whichinterference with the protrusion portion 210 is avoided.

The second cutting edge 123 b of the pouch-type secondary battery 100according to an exemplary embodiment may be formed to have an angle ofinclination A2 of 5° to 15° with respect to one edge of theaccommodating portion 121 adjacent to the lead tab portion 111.

In other words, a range of the angle of inclination A2 of the secondcutting edge 123 b formed farther to the lead tab portion 111 than thefirst cutting edge 123 a is defined.

The angle of inclination A2 of the second cutting edge 123 b is definedas 15° or less to extend a portion of the indent portion 123 formed ofthe second cutting edge 123 b together with the first cutting edge 123 abe a significant area. That is, the angle is defined to form the indentportion 123 in an area in which interference with the protrusion portion210 is avoided.

The angle of inclination A2 of the second cutting edge 123 b is definedas 5° or above so that a portion around the sealing portion 122, inwhich the second cutting edge 123 b is formed, is prevented from beingfolded by an external force.

Further, the rounded edge 123 c of the pouch-type secondary battery 100according to an exemplary embodiment may be formed to have a radius ofcurvature of 2 mm to 8 mm.

The rounded edge 123 c is formed between the cutting edges 123 a and 123b such that when the cutting edges 123 a and 123 b are formed forforming the indent portion 123, burring or cracking can be preventedfrom occurring between the cutting edges 123 a and 123 b.

The rounded edge 123 c is defined as having a minimum radius ofcurvature of 2 mm to prevent burring or cracking from occurring.

The rounded edge 123 c is defined as having a maximum radius ofcurvature of 8 mm to prevent the area of the indent portion 123 formedof the cutting edges 123 a and 123 b from being significantly reduced.That is, it is to extend the area of the indent portion to a significantregion, and is a range allowing to form the indent portion, and is arange allowing the indent portion 123 to be formed in an area in whichinterference with the protrusion portion 210 is avoided.

FIG. 2 is a planar view illustrating the pouch-type secondary battery ofthe present disclosure. Based on FIG. 2 , a first cutting edge 123 a ofthe pouch-type secondary battery 100 according to an exemplaryembodiment, as compared to the second cutting edge 123 b, is formed tobe closer to the lead tab portion 111 and to be shorter.

As described above, relative lengths of the first and second cuttingedges 123 a and 123 b are defined to maximize an area in which theindent portion 123 is formed.

As an example, in the case in which the lead tab portion 111 is formedadjacent to a shorter edge 121 b of the accommodating portion 121, thefirst cutting edge 123 a relatively close to the lead tab portion 111 isformed to be shorter than the second cutting edge 123 b relatively faraway from the lead tab portion 111 such that the indent portion 123 isformed in a widest area while not allowing any damage to be caused inthe lead tab portion 111.

Alternately, in the case in the case in which the lead tab portion 111is formed adjacent to a longer edge 121 a of the accommodating portion121, the first cutting edge 123 a is formed to be longer than the secondcutting edge 123 b such that the area, in which the indent portion 123is formed, is maximized.

FIG. 3 is a planar view illustrating an exemplary embodiment in which alead tab portion in the pouch-type secondary battery is offset. Based onFIG. 3 , in the pouch member 120 of the pouch-type secondary battery 100according to an exemplary embodiment, when the lead tab portion 111 isarranged adjacent to one edge of the accommodating portion 121 and isoffset to one side, the cutting edges 123 a and 123 b of the indentportion 123 formed in an area enlarged by the offset arrangement of thelead tab portion 111 is formed at a gentle angle of inclination ascompared to the cutting edges 123 a and 123 b of the indent portion 123formed in an area reduced by the offset arrangement of the lead tabportion 111.

In other words, when the lead tab portion 111 is arranged adjacent toone edge of the accommodating portion 121 and is offset to one side,angles of inclination of the cutting edges 123 a and 123 b formed in thearea enlarged by the offset arrangement of the lead tab portion 111 andthose in the area reduced are defined.

The cutting edges 123 a and 123 b formed in the area enlarged by theoffset arrangement of the lead tab portion 111 have a gentle angle ofinclination than those in the area reduced are defined. This is toprevent a portion around the sealing portion 122 from being folded bythe indent portion 123 formed in the area of the sealing portion 122enlarged by the offset arrangement of the lead tab portion 111.

In contrary thereto, the cutting edges 123 a and 123 b formed in thearea reduced by the offset arrangement of the lead tab portion 111 areformed to have a steeper angle of inclination than those in the areaenlarged reduced. This is to maximize the area, in which the indentportion 123 is formed, in the area of the sealing portion 122 reduced bythe offset arrangement of the lead tab portion 111.

FIG. 4 is a planar view illustrating the pouch-type secondary batteryand a battery module including the same. Based on FIG. 4 , a pouch-typesecondary battery 100 of another example embodiment and a battery moduleincluding the same may include the pouch-type secondary battery 100 anda housing member 200 in which a plurality of the pouch-type secondarybatteries 100 are accommodated.

The pouch-type secondary battery 100, by including the pouch member 120formed in the previously described indent portion 1213, can enlarge aninternal space of the accommodating portion 121 configured toaccommodate the electrode assembly 110 while avoiding interference withthe indent portion 210 formed in the housing member 200 when thepouch-type secondary battery 100 is mounted on the housing member 200.

That is, a problem in which an entire size of the pouch-type secondarybattery 100 is reduced due to an insufficient installation space by theprotrusion portion 210 formed to fasten inside the housing member 200,which may arise when the pouch-type secondary battery 100 is built in ahousing member 200, or the like, of the battery module, may be remedied.

As the above, the indent portion 123 of the battery module according toanother exemplary embodiment is formed in a position corresponding tothe protrusion portion 210 provided in the housing member 200.

Accordingly, a problem in which a maximum size of the pouch member 120is reduced as the sealing portion 122 is caught by the protrusionportion 210 can be remedied, and a size of the accommodating portion 121of the pouch member 120 is increased to improve capacity of theelectrode assembly 110.

According to the aforementioned example embodiments, the pouch-typesecondary battery and the battery module including the same areadvantageous in that the problem of battery capacity relatively reducedby the area occupied by the sealing portion in the secondary battery maybe remedied.

In another aspect, the pouch-type secondary battery and the batterymodule including the same is advantageous in some exemplary embodimentsin that the sealing portion adjacent to the indent portion may beprevented from being folded.

Meanwhile, the pouch-type secondary battery and the battery moduleincluding the same in some exemplary embodiments are advantageous inthat problems of burring or cracking can be prevented from occurringwhen the indent portion is formed.

Various advantages and beneficial effects of the present disclosure arenot limited to the above descriptions and may be easily understood inthe course of describing the specific embodiments of the presentdisclosure.

While the example embodiments have been shown and described above, itwill be apparent to those skilled in the art that modifications andvariations could be made without departing from the scope of the presentinvention as defined by the appended claims.

What is claimed is:
 1. A pouch-type secondary battery comprising: anelectrode assembly; and a pouch member comprising an accommodatingportion configured to accommodate the electrode assembly therein, and asealing portion formed at outer edges of the pouch member adjacent tothe accommodating portion, wherein the sealing portion includes at leastone indent portion adjacent to a corner of the accommodating portion,wherein the at least one indent portion includes a first cutting edge, asecond cutting edge and a rounded edge connecting the first and secondcutting edges, and wherein the first cutting edge is cut at a firstcutting edge angle, and the second cutting edge is cut at a secondcutting edge angle.
 2. The pouch-type secondary battery of claim 1,wherein the at least one indent portion is formed adjacently to one sideof a lead tab portion of the pouch-type secondary battery, wherein thelead tab portion is externally exposed and is connected to the electrodeassembly.
 3. The pouch-type secondary battery of claim 2, wherein thefirst cutting edge is inclined in a direction away from the lead tabportion; and the second cutting edge is formed at a gentle angle ofinclination as compared to an angle of inclination at which the firstcutting edge is formed.
 4. The pouch-type secondary battery of claim 3,wherein the first cutting edge has an angle of inclination of 10° to 50°with respect to one edge of the accommodating portion adjacent to thelead tab portion.
 5. The pouch-type secondary battery of claim 3,wherein the second cutting edge has an angle of inclination of 5° to 15°with respect to one edge of the accommodating portion adjacent to thelead tab portion.
 6. The pouch-type secondary battery of claim 3,wherein the first cutting edge, as compared to the second cutting edge,is formed closer to the lead tab portion and is shorter.
 7. Thepouch-type secondary battery of claim 2, wherein, in the pouch member,when the lead tab portion is arranged adjacent to one edge of theaccommodating portion and is offset to one side, a cutting edge of theat least one indent portion formed in an area enlarged by the offsetarrangement of the lead tab portion is formed at a gentle angle ofinclination as compared to a cutting edge of the at least one indentportion formed in an area reduced by the offset arrangement of the leadtab portion.
 8. The pouch-type secondary battery of claim 1, wherein therounded edge is formed to have a radius of curvature of 2 mm to 8 mm. 9.A battery module, comprising: the pouch-type secondary battery of claim1; and a housing member accommodating a plurality of the pouch-typesecondary batteries therein, and wherein the at least one indent portionis formed in a position corresponding to a protrusion portion providedin the housing member.
 10. The battery module of claim 9, wherein thehousing member includes four protrusion portions at four cornersthereof, and the pouch-type secondary battery includes four indentportions formed in respective positions corresponding to the protrusionportions.
 11. The pouch-type secondary battery of claim 1, wherein thepouch member has three sealed sides and one non-sealed side.
 12. Asecondary battery comprising: an electrode assembly; a pouch memberincluding an accommodating portion for accommodating the electrodeassembly therein, a sealing portion at outer edges of the pouch memberforming three sealed sides which extend laterally from the accommodatingportion, and a non-sealed side extending substantially in parallel toone side of the electrode assembly; a lead tab portion extending througheach of two opposite sealed sides of the pouch member; wherein thesealing portion includes four indent portions at four corners thereofcorresponding at four corners of the pouch member reducing the areaoccupied by the sealing portion, wherein the electrode assembly isarranged so as to be biased toward the non-sealed side of the pouchmember.
 13. The secondary battery of claim 12, wherein each indentportion includes a first cutting edge, a second cutting edge and arounded edge connecting the first and second cutting edges, and whereinthe first cutting edge is cut at a first cutting edge angle, and thesecond cutting edge is cut at a second cutting edge angle.
 14. Thesecondary battery of claim 12, wherein each of the two indent portionsthat are formed at the sealing portion corners of a sealed side oppositeto the non-sealed side of the pouch member, starts from an outermostedge point of the sealing portion that is aligned with a side of theaccommodating portion and terminates at an outermost edge point of thesealing portion that is aligned with a consecutive side of theaccommodating portion.
 15. The secondary battery of claim 12, whereinthe indent portions are formed adjacently to both sides of the lead tabportions of the electrode assembly.
 16. The secondary battery of claim13, wherein the first cutting edge is inclined in a direction away froman adjacent lead tab portion; and the second cutting edge is formed at aless sharp angle of inclination, as compared to an angle of inclinationat which the first cutting edge is formed.
 17. The secondary battery ofclaim 16, wherein the first cutting edge has an angle of inclination of10° to 50° with respect to one edge of the accommodating portionadjacent to the adjacent lead tab portion, and wherein the secondcutting edge has an angle of inclination of 5° to 15° with respect toone edge of the accommodating portion adjacent to the adjacent lead tabportion.
 18. The secondary battery of claim 16, wherein the firstcutting edge, as compared to the second cutting edge, is formed closerto the adjacent lead tab portion and is shorter.
 19. The secondarybattery of claim 12, wherein, in the pouch member, when the lead tabportion is arranged adjacent to one edge of the accommodating portionand is offset to one side, a cutting edge of the indent portion formedin an area enlarged by the offset arrangement of the lead tab portion isformed at a gentle angle of inclination as compared to a cutting edge ofthe indent portion formed in an area reduced by the offset arrangementof the lead tab portion.
 20. The pouch-type secondary battery of claim12, wherein the rounded edge is formed to have a radius of curvature of2 mm to 8 mm.